Margarson, who rode four winners as a National Hunt jockey, took out a licence last year after spending the previous 15 campaigns as assistant to Mick Ryan and enjoyed three victories in 1996.
Jay Gee, bearing the initials of his owner John Guest, gave him his seventh career win with a courageous success in the pounds 22,000-added six-furlong contest.
Taking over in front for Gary Carter inside the final quarter mile, the Second Set filly was challenged almost immediately by Clef Of Silver. However, the William Jarvis runner found less than expected once surrendering her bridle and Jay Gee surged to a two-length victory, the pair having drifted away from the crowd towards the far rail.
Margarson, who trains locally, was elated. "She is improving all the time and she will be better as a three-year-old, being by Second Set - he didn't run at two," he said. "She has still got growing pains and I will try and pick up a Listed race abroad, possibly at Longchamp, with her at the back-end. She will stay further _ she won this race by staying."
Carter was completing a near 48-1 double, having teamed up with Margarson's former boss Ryan to take the Ye Olde Oak 'Any Time Snacks' Handicap. Half a furlong from the line and it was Swift and Jason Tate who looked on course for victory. But Carter and Silk St John dashed up the stands' side to lead 50 yards out and prevail by a cosy half-length.
John Ryan, assistant to his father, confirmed that tactics went as planned. "I told Gary to leave it until the last minute and you can't do much better than that," he said.
Seb Sanders also rode a 179-1 double. Sanders moved on to the 69-winner mark for the year aboard Michael Stoute's Mohawk River, who came late under top-weight in the concluding 'Ready Rice' Handicap.
Earlier, the jockey had combined with James Toller and the Duke of Devonshire, for whom he rode 50-1 July Cup winner Compton Place here last month, to land the EBF Carters Soft Drinks Maiden Stakes, the Generous colt making most to win by four lengths and earn a 25-1 quote with Coral for next year's 2,000 Guineas.
At those odds he is eight points shorter than Almutawakel, who justified odds of 2-9 for Richard Hills in the opening Hero Stakes.Reuse content